Solve for $x$ : $-18 + x = 24$
Solution: Add $18$ to both sides: $ \begin{eqnarray} \\ -18 + x &=& 24 \\ \\ {+18} && {+18} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-18 + x} &\hphantom{=}& \hphantom{24} \\ x &=& 24 {+ 18} \\ \end{eqnarray} $ Simplify. $ x = 42$